A detailed study is made of matrix-valued, ordinary linear differential operators T in \documentclass[12pt]{minimal}
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\begin{document}$$L^{p}({\mathbb{R}},{{\mathbb{C}}^{N}})$$\end{document} for 1 < p < ∞, which arise as the perturbation of a constant coefficient differential operator of order n ≥ 1 by a lower order differential operator \documentclass[12pt]{minimal}
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\begin{document}$$S = {\sigma_{j=0}^{n--1}} F_{j}(x)(--i\frac{d}{dx})^{j}$$\end{document} which has a factorisation S = AB for suitable operators A and B. Via techniques from Lp-harmonic analysis, perturbation theory and local spectral theory, it is shown that T satisfies certain local resolvent estimates, which imply the existence of local functional calculi and decomposability properties of T.